Accelerator compound and process of preparing same



Patented Mar. 12, 1935 Donald H. Powers, Pennsgrove, N. J., assignor tov E. I. du Pont de Nemours & Company, Wil mington, Del., acorporation'of Delaware No Drawing. Application October 9,1926,

Serial No. 140,692

25 Claims.

This invention relates to a new class of products and to the process ofpreparingthe same. More specifically, it relates to a class of compoundsresulting from the interaction of analdehyde, a primary amine and carbondisulphide.

The invention has as its primary. object the production of novelcompounds of valuable characteristics. In particular, it is the objectof the invention to i produce compounds "especially adapted toaccelerate the vulcanization of rubber and which will, when employed asaccelerators, reducethe time requiredfor satisfactory vulcanization,and*yield a rubber product of superior quality and durability.

This application is in the nature of a continuation, in part, of myapplication Serial N 0. 34,732, filed June 3, 1925, now Patent 1,732,532dated October-22, 1929, which covers products resulting fromthe-interaction-of an aldehyde, a primary amine; 'and' carbon disulphideand the employment of these products as vulcanization accelerators Ihave now discovered that those aldehydes containing a plurality ofcarbonatoms are particularly valuable for the manufacture of prod-' ucts.ofthe accelerator type. Also, I-have dis-' covered that, if certainratios of the three 'components, which ratios were not specificallydisclosed in the previous 'application, are'employed, products of veryunusual activity as accelerating agents result. Particularly, I havediscovered that the use of two, three or four moles of an aldehyde withone mole'of amine gives compounds of remarkable activity. The aminesand" aldehydes used may be either'aliphatic'or aromatic, although in thepreferred embodiments of my inventionI employed aliphatic aldehydes. Thecompounds resulting are of indefinite composition.. I s

The method of manufacturing these new-accelerators maybe varied. Onemethod of preparing them is to condense the aldehyde with the amine toform a condensation product, with the elimination of water, and to thentreat this prodnot with carbon disulphide. By equation, the reactionmight be expressed as follows:

I Ithas also been found that by mixing the amine, CS2 and. aldehydethata product of similar accelerating activity is obtained. 1 "Thepreparation of the new accelerators may be best-disclosed by thepresentation of a number of-examples embodyingthe invention. It is to beunderstood that these examples are-purely illustrative and that theconditions, reagents and proportions therein specified are susceptibleof variation. The examples follow:

Example 1.-3l0 lbs. butyraldehyde areslowly added in a closed system tolbs. of aniline in a kettle equipped with a jacket, a coil for heatingand cooling, and an agitator. The temperature is kept below 50 C. duringaddition of butyraldehyde. After the addition is complete the mixture isslowly heatedto C. and kept at this temperature for one hour. The waterformed is then allowed to separate as a'lower layer and drawn off. Theproductis cooled to .30? C. and 80 lbs. carbon disulphide are added inaclosed system using the usual precautions necessary in handling thismaterial. The temperature is raiseclto .80 C. and held there for. oneand. onehalf (1. /g.) hours. At the end of this time the reactionproduct is cooled to50 C. and any unreacted volatile matter drawn ofi bythe use of, a. high vacuum. The remaining oil is drawn off andcollectedin the usual manner. A product made in the above manner and tested in apure gum mix in a percentage of 0.375 gave a good cure in thirty (30)minutes at twenty-five (25) lbs. steam pressure. The quantities ;em-'-played in this example correspond to 4 molesof aldehyde, 1 mole'ofaniline, and 1 mole of carbon disulphide.

Example 2.285'1bs. heptaldehyde and lbs. butyraldehyde are addedslowly'to 92 lbs. of. ani-.

line. After the addition is complete the mixture is slowlyheatedt0140'C. and held for one hour. The water formed isthen allowed toseparate. as a lower layer and drawn off. The product is'then cooled to30C. and '80 lbs. ofcarbon disulphide are added and thereadtioncompletedas in Example 1. Aproduct made in the above manner and tested in a puregum mixi'n a-percentage'of 0.350 gave a good cure in thirty (30)minutes' at twenty -five (25) lbs. steam. pressure. ,The quan-- titiesemployed in this example correspondto'5 moles of aldehyde, 1 mole ofaniline and 1.1 moles of carbon disulphide. g

7 Example 3.-930'1bs. butyraldeh de'are added to 250 lbs. of cooled 40%aqueous solution of methyl amine. This mixture is heated in a closedsystem to 110 C. for three hours. The water is drawn off or may beremoved by a vacuum distillation. One hundred and thirty pounds of'carbon disulphide are added and the reaction is completed as in Example 1.This product using'0.'3 parts in a mix containing one hundred partsofpale crepe, three parts of sulphur and three parts of zinc oxide gave agood cure in an hour at twenty-five pounds steam pressure. Thequantities employed in this example correspond to 4 moles of aldehyde, 1mole of amine and 0.53 mole of carbon disulphide.

Example 4. 225. lbs. benzaldehyde are slowly added to 75 lbs. of normalbutyl amine. The mixture is heated under pressure for two hours at 150C. The water is removed by vacuum distillation and 80 lbs. carbondisulphide added. This product is heated to 100 C. under. pressure foran hour, cooled and the uncombined carbon disulphide removed under highvacuum. The resulting product tested in a pure 'gummix, three percentzinc oxide and three and a half percent sulphur gives a good cure inanhour at 40 lbs. steam pressure when three-quarters 'of one percent isused. The quantities employed in this example correspond to 2.1 moles ofaldehyde, 1 mole of amine and 1 mole of carbon disulphide.

'Example 5.An example of the alternative" method of manufactureof-accelerator. compounds by mixing the amine, and aldehyde all at oncefollows:

350 lbs. heptaldehyde .are mixed-with 80 lbs. of carbon bisulphide andto this mixture 110 lbs. of p-toluidine. are added slowly. The mixtureis then heated slowly to-litl C. and-held for one hour. The water formedis then allowed to separate and drawn off. Any unreacted volatile matteris then drawn off under vacuum. The product, made in the above manner,and tested in a pure gum mix in a percentage of 0.325 gave a good curein 30 minutes at 25 lbs. steam pressure. The quantities employed inthisexample correspond to 3 moles of aldehyde, l'mole of amine andlmole ofcarbon disulphide. z.

1 Products having similar. accelerating activit to those prepared bytreating the amine first with the aldehyde and'then with CS2, may beprepared ineach instance by this alternative method.

- While I have mentioned for purposes of illustration definitequantities of v the. reacting components and certain specifictemperatures and times of reaction, and in general have givenexactconditions under which'my improved compounds Imay be made, I, ofcourse, do not limit myself to these specific proportions orconditions.These illustrative conditions and methods'of effecting the interactionand combination. of the ingredients may obviously be varied withoutdeparting from my invention... In cases where .I use more than onealdehyde I may use other aldehydes than those specified in Example 3,also more than ,one amine or a mixture of aromatic and aliphatic aminesmay be used. As little as one half a mole of carbon disulphide for. eachmole ofv amine may beemployed, I

The products of the inventionare very highboiling viscous liquids, darkin color and with a characteristicv odor. An increase in the proper-Jtion of-,'al dehyde employed increases their accelerating activity. Anincrease in'the proportion of carbon bisulfide :also, of course,resultsin an' increase in the accelerating activity due to the greateramount of combined sulfur present. All of the products of the typedisclosed inthe exam-. ples, however, exhibit marked effectiveness asaccelerators for the vulcanization of rubber.

The products obtained, as illustrated in the examples, are of indefiniteconstitution but, as indicated by the equation preceding-theexamples,contain in combination all-of the elements of the respective reagentswiththe exception of the water eliminated. h

In the claims where I specify a primary aromatic amine, I intend tocover, also, the substituted primary aromatic amines as aniline and itshomologues. Where I specify rubber I intend to cover all the botanicalvarieties of caoutchouc, which include vhevea, balata, gutta percha,etc. and recognized substitutes therefor.

I claim:

1. A dark, high-boiling, viscous liquid or resinous solid obtained bythe chemical combination, in the absence of substantial quantities ofadded acid, of an aldehyde, a primary aromatic amine, and carbonbisulphide, with the elimination only of water.

. 2. A product such as covered by claim 1, in which two to four moles ofaldehyde are employed to one mole of amine.

3. A product such as covered by claim 1, in

,which more than 2 moles of aldehyde are employed to one mole of amine.

4. A dark, high-boiling, viscous liquid or resinous solid obtained bythe chemical combination,

in the absence of substantial quantities of added acid, of an aliphaticaldehyde containing a pluralityof carbon atoms, a primary amine, andcarbon. bisulphide, with the .elimination:only of water.

5. A dark, high-boiling, viscous liquid or resinous solid obtained bythe chemical combination; in the absence of substantial quantities ofadded acid, of an aliphatic aldehyde containing a plu-.

rality of carbon atoms, aprimary aromaticamine, and carbon bisulphide,with the eliminationzonly ofwater.

6. I A dark, high-boiling,.-viscous'liquid or resinous solid obtained bythe chemical combination, in the absence of substantial quantities ofadded acid, of an aliphatic aldehyde containingaplurality of carbonatoms, aniline, and carbon bisulphide, with the elimination only ofwater.

I v7. The product set forth in claim 6 in which two to four moles ofaldehyde are employed to one mole of amine. s

- 8. A' dark, high-boiling viscous liquid obtained by thechemicalcombination, in the absence of substantial quantities of addedacid, of butyraldehyde,.aniline, and carbon bisulphide, with theeliminationonly of water.

,9. A dark, high-boiling viscousliquid or resinous solid obtained bycausing carbon bisulphide to; react on the condensation product of aprimary aromatic amine and. an-aldehyde containing aplurality ofcarbonatoms, with the elimination only of water. 1

10. The product/set forth in, claim 9, in which two to fourmolesofaldehyde are employed to one mole of amine. j' 3 I 11. A dark,high-boilingv viscous liquid or resinous solid obtained by causingcarbon bisulphide to react on the. condensation productof a-primary'aromatic amine and butyraldehyde.

; 12. The product set forth in claim 11 in which which comprisesinteracting, in the absence of substantial quantities of added acid,substantially one mole of a primary amine, more than one mole of analdehyde and carbon disulphide, with the elimination only of water.

16. The process of preparing a new compound which comprises interacting,in the absence of substantialquantities of added acid, substantially onemole of a primary amine, more than one mole of an aliphatic aldehyde andcarbon disulphide, with the elimination only of water.

17. The process of preparing a new compound which comprises interacting,in the absence of substantial quantities of added acid, substantial- 1yonemole of a primary aromatic amine, more than one mole of an aliphaticaldehyde and carbon disulphide, with the elimination only of water.

18. The process which comprises causing carbon bisulphide to react onthe condensation product of a primary amine and an aldehyde containing aplurality of carbon atoms, with the elimination only of water.

19. The process set forth in claim 18 in which two to four moles of analdehyde are employed to one mole of amine.

20. The process which comprises causing car bon bisulphide to react onthe condensation product of a primary aromatic amine and an alde-- hydecontaining a plurality of carbon atoms, with the elimination only ofwater.

21. The process which comprises causing carbon bisulphide to'react onthe condensation product of a primary aromatic amine and an aliphaticaldehyde containing a plurality of carbon atoms, with the eliminationonly of water.

22. The process set forth in claim 21 in which two to four moles ofaldehyde are employed to one mole of amine.

23. The process of preparing a new compound which comprises causingcarbon bisulfide to react on a condensation product .of aniline andbutyraldehyde. 1

24. The process of preparing an accelerator comprising the reacting ofcarbon disulphide upon the preformed reaction product of an aliphaticaldehyde and an aromatic primary amine, said aldehyde-amine productbeing obtained by combining at least one mol of said aldehyde with onemol of an amine.

25. As a new product an accelerator prepared by reacting carbonvdisulphide upon the pre--- formed reaction product of an aliphaticaldehyde and an aromatic primary amine, said aldehydeamine product beingobtained by combining at least one mol of said aldehyde with one mol ofan amine. v

I DONALD H. POWERS.

